import { useEffect, useState } from 'react'
async function queryData(){
    const data = await new Promise((resolve)=>{
        setTimeout(()=>{
            resolve(666)
        },2000)
    })
    return data
}
function App(){
    const[num,setNum] = useState(0)
    useEffect(()=>{
        queryData().then((data)=>{
            setNum(data)
        })
    },[])
    return(
        <div onClick={()=>{
            setNum((preNum)=>{
                return preNum+1
            })
        }}>
            {num}
        </div>
    )
}
export default App